This invention relates to functional electrical stimulation (FES) of paraplegics and more particularly to an improved microcomputer controlled apparatus and methodology. Work on functional electrical stimulation of paraplegics is based on the discovery of the Italian physiologist Luigi Galvani in the late 18th century that a muscle will contract when in contact with an electrical charge. This has been first applied systematically to paralyzed patients by W. Liberson in 1960 (in W. Liberson et al., Arch. Phys. Med. Rehab., Vol. 42, p. 101, 1961). Since then considerable work has been devoted to that topic, as reviewed by Graupe et al. (J. Biomed Eng. Vol. 5, pp. 220-226, July 1983), by Graupe et al. (Critical Reviews in Biomedical Engineering, CRC Press, Vol. 15, pp 187-210, 1988) and in a recent text by A. Kralj and T. Bajd ("Functional Electrical Stimulation: Standing and Walking after Spinal Cord Injury", CRC Press, Boca Raton, Fl, 1989).
It was thus shown that the application of trains of pulses of adequate amplitude, pulse-width and pulse-repetition-frequency at appropriate locations above the region of certain key muscle, enables paraplegic patients with complete or near-complete upper-motor-neuron lesions to stand up and to take steps with the support of parallel bars or a walker. The merits of such standing and of the primitive walking accomplished by these steps is both psychological and physiological in the exercise provided to the patient which enhances circulation, cardiac output and movement of joints to prevent or slow down ossification and contractures (Kralj and Bajd, "Functional Electrical Stimulation: Standing and Walking after Spinal Cord Injury," CRC Press, Boca Raton, Fla., 1989, pp. 33, 68, 130-131). Furthermore, there are indications (not yet fully proven due to the limited application of FES which is presently available only in research labs and research clinics), that FES is beneficial in prevention or reduction of incidence of pressure sores and of osteoporosis (Krajl and Bajd, same as above, pp. 8, 33, 49, 69, 131 and 135) and in the reduction of severity of spasticity (Krajl and Bajd, same as above, pp. 3, 8, 37-47). FES is limited to upper-motor-neuron lesions since in that case the peripheral nerves (at the lower extremities, in our case) are intact though they cannot communicate with the central nervous system due to the spinal-cord lesion. However, since the peripheral nerves are healthy and intact, they respond to FES even after many years of paralysis without stimulation. In two patients, after 35 years of paralysis and with no stimulation over that whole time, the peripheral nerves responded to FES fully satisfactorily.